1. Field of the Invention
The instant invention is directed to further advanced methods of and apparatus for manipulating electromagnetic phenomenon. To further convey information, utilizing substantial portions of visible and invisible spectra and to further manipulate information, whether that information is in the form of pictorial displays, such as holographic displays; in the form of numerical information, such as digital or analog numerical information; or in the form of communication signals, wherein the signals are selected from any portion of the electromagnetic spectrum.
2. Prior Art
One of a number of fields to which the instant invention applies is the field of holography. In order to create a holographic image, it is necessary to superimpose two coherent light beams, which are incident on the same photographic plate/means or other suitable recording device. One beam is known as the “object beam” and the other beam as the “reference beam”. In off-axis holography, the beams are separated by an angle θ, which is typically 45°. The term “off-axis” is used because the angle, θ, between the beams results in the axis of the beams not being coaxial. The general equation of holography has some complexity and does not lend itself to any solution other than a numerical solution, see Method of and Apparatus for the Manipulation of Electromagnetic Phenomenon, U.S. Pat. No. 5,369,511 incorporated by reference herein. In accordance with the practices of the prior art, a reference wave or pure “plain wave”, is mixed with modulated object information (object wave). It can be readily seen that if the angles between the waves Rθ and Oθ approximately equal zero, then the beams or waves are essentially coaxial. The result is “in-line” holography. However, the problem which presents itself is that these prior art approaches have not produced viable holograms because prior art in-line systems are prone to double images, zero-order aberrations, or both. While holography is generally considered to be a phenomenon primarily of interest with respect to the entire electromagnetic spectrum for the display of images utilizing complex light beams or manipulation of optical information utilizing laser beams, many of the same principles, which are applicable to visible light are also applicable to other portions of the electromagnetic spectrum such as infrared and ultraviolet radiation, radio waves and X-rays. There still is a need for new devices, which further extends the optical principles utilized in holography to effectively create practical, working, robust Transmission and Reflection on-axis, in-line, holograms.